In order to select a suitable LiFePO4 smart BMS, the following factors are to be considered:
- Battery system voltage and capacity: The selection of a BMS solution is related to the size of the battery system and, most importantly its rated voltage and capacity. Ensure the BMS aligns with your LiFePO4 battery’s specifications. For example, if you purchase a 12V battery pack, you should use a BMS rated for 12V.
- Current: You need to determine the maximum power (in Watts) required, which will determine the current required. Remember Power (W) = Voltage (V) x Current (A). For example, if you plan to build a 3000W solar system and want to supply it with a maximum load of 2500W, you need to select a BMS that can support this power. in the example, a 100A BMS was selected, but by doing the math, it turns out that it will not be able to support a 3000W system.
- Battery pack voltage: If the voltage of your battery pack is not 12V but some other value such as 24V or 48V, you need to adjust the voltage and current rating of the BMS accordingly to ensure compatibility.
- Rated capacity and C-rate: You can also use the pack’s rated capacity and C-rate to determine the BMS required. e.g. if the pack has a capacity of 200Ah and a maximum C-rate of 0.2C, then you will need to select a BMS capable of handling at least 40A as 200Ah × 0.2C = 40A (maximum current that can be supplied over a 5-hour period).
MORE: How do I know if LIFEPO4 battery BMS is working properly?